Monday, January 27, 2020

Rafiniesquina robusta Brachiopod from the Coburg Fm.

I have found a number of Strophomenid type brachiopods on my trips to collect in the St. Mary's Cement Quarry, but it is hard to distinguish between them some times. The two specimens below I believe are Rafiniesquina robusta, based on William Hessin's book, "South Central Ontario Fossils". The shell is a good size and highly convex with the margins extending perpendicularly to the valves for a good distance. Unfortunately the pedicle valve is not visible or I could look for other unique features to help identify the fossil.

Specimen #1 pedicle valve

Specimen #1 anterior

Specimen #1 left profile

Specimen #1 right profile

Specimen #2 pedicle valve

Specimen #2 anterior

Specimen #2 left valve

Specimen #2 right valve

The Coburg formation is Ordovician in age (late Ordovician, Katian/Mohawkian stage).
These fossils were collected from the St. Mary's Limestone Quarry in Bowmanville, Ontario. I used William Hessin's book "South Central Ontario Fossils", 2009, Self Published, pg. 127-128 to help identify them.

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